1
: forming or relating to the most important part of something : basic
The Constitution ensures our fundamental rights.
There's a fundamental difference between these two political parties.
a fundamental truth/concept/belief
—often + tobeliefs that are fundamental to our society
2
: of or relating to the basic structure or function of something
These ideas are of fundamental importance.
The revolution brought about a fundamental change in the country.
We need to make some fundamental changes in the way we do business.
We need to address these problems on a more fundamental level.
plural fundamentals
: one of the basic and important parts of something : a fundamental part
—usually plural
Reading, writing, and arithmetic are the fundamentals of education.
the fundamentals of algebra
Cite this Entry
“Fundamental.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/fundamental. Accessed 29 Jun. 2026.
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